Management of Growing Non-Functioning Adrenal Adenoma
This patient requires adrenalectomy because the lesion has grown 1 cm over the time period (>5 mm/year growth threshold), and repeat hormonal workup should be performed before surgery. 1, 2
Growth-Based Surgical Indication
Your patient's adenoma has grown from 2.5 cm to 3.5 cm (1 cm total growth). The critical decision point is the growth rate of >5 mm/year, which mandates surgical consideration after repeating functional workup. 1, 2
- Growth <3 mm/year requires no further imaging or testing 1, 3
- Growth >5 mm/year requires adrenalectomy consideration after repeating hormonal evaluation 1, 2, 3
- The American Urological Association explicitly states that continued growth mandates intervention and surveillance should not continue indefinitely 2
Pre-Operative Hormonal Re-Evaluation
Before proceeding to surgery, repeat the complete hormonal workup even though the initial evaluation was normal. 2, 3 This is critical because:
- Approximately 5% of radiologically benign incidentalomas develop subclinical hormone production requiring treatment 2, 3
- One case series documented a patient who developed cortisol hypersecretion after 24 months of follow-up in a previously non-functioning 3.5 cm adenoma 4
- Undiagnosed pheochromocytoma can cause life-threatening intraoperative hypertensive crisis 2, 3
Required Pre-Operative Testing:
- Pheochromocytoma screening: Plasma or 24-hour urinary metanephrines (mandatory before any surgery) 1, 3
- Autonomous cortisol secretion: 1 mg overnight dexamethasone suppression test 1, 3
- Primary aldosteronism (if hypertensive or hypokalemic): Aldosterone-to-renin ratio 1, 3
Surgical Approach
Minimally invasive (laparoscopic) adrenalectomy should be performed when feasible for this 3.5 cm lesion. 1, 2, 3
- Laparoscopic approach is appropriate for lesions up to 6 cm that can be safely resected without capsular rupture 1, 2
- Open adrenalectomy should be reserved for larger tumors or those with features suggesting adrenocortical carcinoma 1
Rationale for Surgery Despite Benign Appearance
While the lesion appears benign (initially <4 cm, non-functioning, normal hormones), the documented growth pattern changes management:
- Historical data shows high incidence of adenoma and carcinoma in non-functioning tumors >3 cm, with potential for malignant degeneration without clinical or endocrine abnormalities 5
- One series found that with the exception of 1 pheochromocytoma, 1 cyst, and 1 myelolipoma, all adrenal incidentalomas larger than 6 cm were carcinomas 4
- A case report documented a 45-year-old woman whose adrenal mass enlarged from 3.2 cm to 4.4 cm over 12 months; the excised lesion proved to be an adenoma, but the growth pattern necessitated removal 4
Critical Pitfalls to Avoid
- Never perform adrenal biopsy as part of workup due to limited clinical value and risks including tumor seeding 3
- Never skip pheochromocytoma screening before surgery, even if initial workup was negative, as this can cause intraoperative crisis 2, 3
- Do not continue surveillance indefinitely when growth is documented—this represents a clear indication for intervention 2
- Avoid laparoscopic approach if imaging suggests malignancy (heterogeneous, irregular margins, >20 HU on non-contrast CT) 1, 3